1. Field of the Invention
The present invention pertains generally to lasers and more particularly to rare gas halide avalanche discharge exciplex lasers.
2. Description of the Background
Substantial output powers have been achieved in the ultraviolet spectral region by the rare gas halide lasers. When employed as avalanche discharge lasers, the KrF exciplex laser achieves large output powers per pulse which is useful in photochemical applications generally, and more specifically, for industrial chemistry to supply energy to specific reactions. Since the KrF avalanche discharge laser has an output wavelength of approximately 248 nm, it is useful in pumping a large number of dyes which have an absorption peak which falls in the 248 nm wavelength spectral region. These dyes can then be used as lasers since they fluoresce and produce coherent photons at various frequencies in the uv and visible spectral regions.
However, many dyes useful for photochemistry applications do not have absorption peaks within the output spectral wavelength of the KrF laser such as, for example, the xenon chloride (XeCl) laser, which has an output wavelength of 308 nanometers, falls within the peak absorption region of many uv dyes. Similarly, the KrF laser has demonstrated a static fill lifetime which is substantially shorter than the XeCl laser, which consequently limits the useful lifetime of the gaseous lasing medium of the KrF laser. Furthermore, to obtain optimum output powers from the KrF laser, high gaseous lasing medium pressures must be maintained within the laser cavity. These required high pressures which introduces other safety and operational problems. For example, the interaction cavity maintained under these high pressure must be both electrically neutral and nonreactive to the gaseous lasing medium. Suitable materials lack the required tensile strength to prevent leakage and warpage of the cavity and simultaneously insure durability over extended operational periods.
3. Statement of the Objects
It is therefore an object of the present invention to provide an improved XeCl avalanche discharge laser.
It is also an object of the present invention to provide an improved XeCl avalanche discharge laser for providing high output powers equivalent to or exceeding KrF avalanche discharge lasers.
Another object of the present invention is to provide an improved XeCl laser which operates near atmospheric pressure.
Another object of the present invention is to provide an improved XeCl laser which is durable in operation.
Another object of the present invention is to provide an improved XeCl laser which uses a substantial portion of Ar diluent gas.
Another object of the present invention is to provide an improved XeCl laser for producing 308 nm wavelength radiation for pumping uv dyes.
Other objects, advantages, and novel features of the present invention will become apparent to those skilled in the art upon examination of the following detailed description of a preferred embodiment of the invention and the accompanying drawings.